Neuroblastic Differentiation of Metastases of Medulloblastoma to Extracranial Lymph Node: An Ultrastructural Study

Extracranial metastases of a poorly differentiated medulloblastoma in a 12-year-old girl were studied by thin section transmission electron microscopy and immunohistochemistry. The primary tumor did not show any differentiation as revealed by immunohistochemistry. On the contrary, the metastatic tumor cells and their processes disclosed features of neuroblastic differentiation when examined ultrastructurally: microtubules, dense core vesicles, and abortive synaptic ribbons. Several dystrophic neurites containing altered subcellular organelles were also found. Furthermore, few processes contained concentric arrays of paired membranes. This report is the first to clearly show the neuronal differentiation of extracranial metastases of poorly differentiated medulloblastoma. We speculate that metastases of medulloblastomas outside the neuraxis behave analogously to medulloblastoma explants cultured in vivo.     

Neuroblastic Differentiation of Metastases of Medulloblastoma to Extracranial Lymph Node: An Ultrastructural Study

Extracranial metastases of a poorly differentiated medulloblastoma in a 12-year-old girl were studied by thin section transmission electron microscopy and immunohistochemistry. The primary tumor did not show any differentiation as revealed by immunohistochemistry. On the contrary, the metastatic tumor cells and their processes disclosed features of neuroblastic differentiation when examined ultrastructurally: microtubules, dense core vesicles, and abortive synaptic ribbons. Several dystrophic neurites containing altered subcellular organelles were also found. Furthermore, few processes contained concentric arrays of paired membranes. This report is the first to clearly show the neuronal differentiation of extracranial metastases of poorly differentiated medulloblastoma. We speculate that metastases of medulloblastomas outside the neuraxis behave analogously to medulloblastoma explants cultured in vivo.     

A Case of Intramural Uterine Stromal Tumor with EpitheliaI Differentiation

A case of intrauterine tumor in a 62 year old Japanese woman is presented. It was thought initially that this was a case of uterine tumor resembling an ovarian sex cord tumor. To examine the cytological features of the tumor cells, electron microscopical and immunohistochemical studies were done, and a hormone assay of the tumor tissue was performed. The tumor cells were rich in rough endoplasmic reticulum (rER), mitochondria and microfila-ments. Some tumor cells tended to form glandular patterns, but these epithelial elements were frequently scattered among fibrous stromal elements. Though many tumor cells with an epithelial appearance possessed a large quantity of cytokeratin and vimentin, they did not secrete estradiol, progesterone, testosterone or human chorionic gonadotropin. This case was finally diagnosed as an intramural uterine stromal tumor with epithelial differentiation after taking all the available data into consideration. This would be classified as an endometrial stromal tumor with epithelial elements, recently proposed and named by Clement and Scully. Acta Pathol Jpn 42: 916–922, 1992.     

The Role of Chromatin Remodeling in Medulloblastoma

The unexpectedly high frequency and universality of alterations to the chromatin machinery is one of the most striking themes emerging from the current deluge of cancer genomics data. Medulloblastoma (MB), a malignant pediatric brain tumor, is no exception to this trend, with a wealth of recent studies indicating multiple alterations at all levels of chromatin processing. MB is typically now regarded as being composed of four major molecular entities (WNT, SHH, Group 3 and Group 4), which vary in their clinical and biological characteristics. Similarities and differences across these subgroups are also reflected in the specific chromatin modifiers that are found to be altered in each group, and each new cancer genome sequence or microarray profile is adding to this important knowledge base. These data are fundamentally changing our understanding of tumor developmental pathways, not just for MB but also for cancer as a whole. They also provide a new class of targets for the development of rational, personalized therapeutic approaches. The mechanisms by which these chromatin remodelers are dysregulated in MB, and the consequences both for future basic research and for translation to the clinic, will be examined here.     

Medulloblastoma with myogenic differentiation showing double immunopositivity for synaptophysin and myoglobin

Reported herein is a case of medulloblastoma with myogenic differentiation in a 3-year-old girl who died 1 year after appearance of clinical signs. Magnetic resonance imaging indicated a mass lesion in the cerebellar vermis. She underwent total resection of the tumor, followed by chemotherapy and radiotherapy in the brain and spinal cord. The resected specimen mainly consisted of densely packed cells with round-to-oval highly chromatic nuclei surrounded by scanty cytoplasm and focally of long spindle-shaped cells with elongated nuclei and eosinophilic cytoplasm showing discernible cross-striations. Immunohistochemistry indicated partial expression of synaptophysin in the former area and focal expression of desmin in the latter area. The diagnosis was medulloblastoma with myogenic differentiation, also known as medullomyoblastoma. Autopsy indicated disseminated proliferation of immature neuroglial cells with highly chromatic nuclei and scanty cytoplasm showing partial expression of synaptophysin, neurofilaments, and GFAP, and focal proliferation of round-to-oval immature cells showing immunoreactivity of myoglobin. The tumor cells had large nuclei, frequent mitoses, apoptoses, nuclear molding, and cell wrapping, indicating moderate anaplasia. Their Ki-67 labeling index was 54%. In addition, some tumor cells had double immunopositivity for synaptophysin or neurofilament and myoglobin, suggesting that the neuroectodermal cells may undergo differentiation into rhabdomyoblasts.     

Prognostic Significance of Ror2 and Wnt5a Expression in Medulloblastoma

Medulloblastoma (MB) is a clinically and biologically heterogeneous group of tumors, and currently classified into four molecular subgroups (Wnt, Shh, Group 3 and Group 4). Intracellular signaling of the Wnt pathway has been divided into two classes: the “canonical” and the “non‐canonical” signaling pathway. The canonical signaling pathway is a well‐established, β‐catenin‐dependent signaling pathway in MB. In contrast, very little research about the non‐canonical WNT signaling pathway in MB exists. In order to identify the roles of Wnt‐5a and Ror2, two non‐canonical WNT pathway‐related genes, we studied 76 cases of MB with immunohistochemistry and quantitative real‐time PCR and correlated the results with clinicopathological and other molecular parameters and prognosis. Wnt5a and Ror2 were immunopositive in 20 (29.4%) and 35 (51.5%) of 68 cases, respectively. There were positive associations among protein expressions of Wnt5a, Ror2 and β‐catenin. Ror2 mRNA levels were well correlated with immunoexpression. Ror2 mRNA expression was significantly associated with CTNNB1 mutation. High Ror2 mRNA expression was an independent favorable prognostic factor. In conclusion, our study demonstrates the first attempt to identify Wnt5a and Ror2 as additional mechanisms contributing to dysregulation of the non‐canonical WNT signaling pathway in MB. Ror2 may play a role as an oncosuppressor in MB.     

小鼠髓母细胞瘤干细胞分离培养及干细胞标记物的分析

目的 旨在建立自发髓母细胞瘤模型小鼠肿瘤干细胞分离培养方法,观察其在体外形成克隆的能力,对可能的肿瘤干细胞标志分子CD44、CD133和CD15进行流式细胞术分析鉴定.方法 将小鼠髓母细胞瘤组织通过温和消化液消化分离成单细胞悬液,于干细胞培养基中培养.计算其细胞球形成率.于含血清培养基中培养观察分化能力.利用流式细胞术对其表面可能的干细胞表面标记分子进行分析鉴定.结果 从模型小鼠髓母细胞瘤组织中成功分离培养髓母细胞瘤原代细胞,原代细胞可形成具有高度的自我更新和增殖能力的细胞球;细胞球可在含血清培养基中贴壁分化成为神经元样细胞;干细胞表面标记分子流式细胞术分析表明髓母细胞瘤干细胞中CD44表达较高,CD133及CD15的表达无差异或者降低.结论 髓母细胞瘤肿瘤细胞中存在一定量的具有自我更新增殖能力、高表达CD44的肿瘤干细胞,并能在体外将其分离培养、连续传代及诱导发生分化.     

Neuroectodermal Differentiation in "Extraskeletal Ewing's Sarcoma"

A small round cell tumor of soft tissue arising in the retroperitoneum of an 18-year old woman is reported. The light and electron microscopic features of the tumor were mostly indistinguishable from Ewing's sarcoma of the bone and in some parts from differentiating neuroblastoma with mature neurons and Schwann cells. An immunohisto-chemical study using anti NSE antibody showed many widespread NSE-positive cells lying singly and, more often, in clusters including the undifferentiated areas. The tumor was not anatomically related to the paravertebral sympathetic ganglia or adrenal glands. The present findings strongly suggest that certain extraskeletal Ewing's sarcomas are very primitive neuroectodermal tumors. Acta Pathol Jpn 39: 795-802, 1989.     

Heparanase Expression and TrkC/p75NTR Ratios in Human Medulloblastoma

Medulloblastoma (MB), the most devastating and common brain tumor in children, is highly invasive and extremely difficult to treat. Identifying the properties of MB tumors that cause them to invade and metastasize is therefore imperative for the development of novel treatments. We performed investigations to elucidate prognostic implications of heparanase (HPSE-1) and TrkC/p75^NTR expression in MB using formalin-fixed, paraffin-embedded (FFPE) MB clinical specimens from children aged 1–19 years. Expressions of p75^NTR and HPSE-1 correlated with each other (Pearson’s correlation R = 0.899; P < 0.0001; R ² = 81%; n = 14). In addition, TrkC:p75^NTR ratios correlated with MB meningeal spread (R = 0.608; P = 0.0212; R ² = 37%; n = 14). Secondly, using antibodies specific to TrkC and HPSE-1, we carried out immunohistochemistry (IHC) on 22 human MB tissue samples. IHC reaction scores revealed a significant expression of HPSE-1 in 76% of MB tissues from children aged 3 years and older (P = 0.0490; n = 17) while TrkC immunoreactivity was detected in 71% of these patient samples. Of note, TrkC was significantly present in 100% of MB female patients (P = 0.0313; n = 6). These studies support the role of p75^NTR and HPSE-1 as two novel molecular determinants involved in the biology and clinical progression of MB.     

ImmunohistochemicaI and UItrastructuraI LocaIization of Epidermal Growth Factor Receptor in Human Liver and Hepatocellular Carcinoma Tissues

Expression of epidermal growth factor receptor (EGF-R) in human hepatocellular carcinoma (HCC), hepatoblastoma and non-cancerous liver tissues was investigated immuno-histochemically in order to evaluate the possible role of EGF-R expression in neoplastic transformation of he-patocytes. lmmunoreactive EGF-R molecules were identified on frozen sections by means of the avidin-biotin im-munoperoxidase complex technique using a monoclonal antibody recognizing an epitope of the external domain of human EGF-R. Linear positive staining was present on the surface of carcinoma cells in one hepatoblastoma and in 9 of 11HCCs. In addition, an enhanced level of surface EGF-R expression was observed on the tumor cells in 9 of 12 cases in comparison with that on hepatocytes in surrounding non-cancerous liver tissue, which in most cases showed chronic inflammation, hepatocyte injury or regeneration. No positive staining in the form of coalescent cytoplasmic granules was present in HCC or hepatoblastoma cells, nor in the cytoplasm of hepatocytes in normal or non-cancerous diseased liver tissue. Little or no reactivity was present on the surface membrane of hepatocytes in the normal liver tissues of 8 control cases. Furthermore, immunoelectron microscopy revealed the localization of this immunoreactive EGF-R molecule on the plasma membrane. Considering that the functional form of EGF-R could be localized on the plasma membrane, the enhanced expression of immunoreactive EGF-R on the tumor cell surface demonstrated here may suggest a possible role of EGF-R in the development or progression of human HCC as well as in hepatocyte regeneration. Acta Pathol Jpn 40: 22–29, 1990.     

The pathology of viral hepatitis in chimpanzees

Summary Serial biopsy specimens (up to 21) of 39 chimpanzees who received inocula of defined infectivity containing hepatitis virus A (9 animals), B (7 animals), and non-A-non-B (24 animals) were evaluated under code for light-microscopic alterations. These studies demonstrated the basic pathologic features seen in human viral hepatitis, although to a lesser degree. These included besides hepatocytic degeneration and necrosis lobular and portal reactions of lymphocytic, macrophagic, and sinusoidal cells. Simultaneously determined serum enzyme activities correlated well with histologic parenchymal changes, indicating that diffuse hepatocytic alterations rather than necrosis are the main substrate of functional alterations. Massive necrosis and chronic active hepatitis were never observed. Hepatitis A and B revealed relatively severe changes which in hepatitis A were restricted to the periportal zone. Hepatitis B had a more prolonged course. Hepatitis non-A-non-B appears to represent a lingering disorder with prolonged low-grade activity but may have a transient period of acute hepatocytic degeneration. The histologic changes appeared earliest in hepatitis A, much later in hepatitis B, and intermediate in time in hepatitis non-A-non-B. The histologic features in the three forms of chimpanzee hepatitis may assist in the light-microscopic differentiation of the three forms in man.Supported by National Institutes of Health NIEHS Grant, Nos. 2 P30 E500928 06 and AM 25553 and Contract No. HB-9-2919     

Cellular blebbing in superficial colonic epithelial cells occurring with murine graft-versus-host disease

Subnuclear blebbing of the superficial colonic epithelium, a rarely described light and electron microscopic change in graft-versus-host disease (GVHD), was studied in a murine model of GVHD. Severity of changes induced by transfer of various donor T cell subsets to irradiated, allogeneic recipients, and association with more severe alterations such as erosions and ulceration were evaluated. By light microscopy the basal region of the superficial enterocytes was greatly expanded by eosinophilic to amphophilic, flocculent, sometimes vacuolated material. By electron microscopy these changes were found to be organelle-poor, cytoplasm-filled protrusions from the basal surface of the epithelium. In this model, helper T cells (CD4+-enriched, CD8+-depleted T cells) transplanted after high dose irradiation were capable of causing the change suggesting cytokine responses may be involved in mediating the cellular injury seen histologically. Close association of blebbing and erosions suggest the blebbing may be the precursor to epithelial erosion or denudation seen in severe intestinal GVHD.     

Changes in microglial cell numbers in the spinal cord dorsal horn following brachial plexus transection in the adult rat

Summary The effect of peripheral nerve transection on the size of the microglial cell population in cytoarchitecturally distinct regions of the spinal cord dorsal horn of rats was evaluated at selected intervals 2 through 35 days after unilateral brachial plexotomy. The identification of cells was verified by electron microscopic examination of a representative random sample of cells included in the counts. Microglial cell numbers were increased in laminae I, II as well as the arbitrarily defined deeper laminae 3.5 days after surgery. Although microglial cell numbers in laminae I were within normal range 35 days after axotomy, those of the more ventrally located laminae remained significantly greater than control values for the duration of the experimental period. These findings demonstrate that: 1) microglial cell proliferation in the dorsal horn is an early event in the central changes that are attendant to peripheral nerve injury 2) the time course of the response varies in cytoarchitecturally different regions.     

Collageless collages — Photographic reconstructions,the easy way,of neurons and other extended objects

Summary A small, movable aperture placed at or near the Köhler field diaphragm location of a light microscope permits making composite high contrast, high clarity photographs of objects, such as Golgi stained neurons, whose extensions in depth are greater than the depth of field of the microscope's objective. The technique is described.     

Atypical Primitive Neuroectodermal Tumors Comparative Light and Electron Microscopic and Immunohistochemical Studies on Peripheral Neuroepitheliomas and Ewing's Sarcomas

Recently, primitive neuroectodermal tumors (PNETs) have been shown to cover a wide spectrum of small round cell sarcomas, probably including some Ewing's sarcomas (ESs) and extraskeletal Ewing's sarcomas (EESs), in addition to classical peripheral neuroepitheliomas (PNs). In studies of small cell sarcomas, we found a group of undifferentiated tumors resembling PNETs with some features of neuroectodermal differentiation, but possessing areas of relatively large, pleomorphic cells. To clarify the nature of these tumors and their relationship to PNETs, we examined the variety of histological, immunohistochemical and ultra-structural features of 11 small cell sarcomas. Five of these tumors were composed of uniform, small round cells and were classified as PNs because of the presence of definite Homer-Wright rosettes and fibrillary processes. The presence of well developed neurite like processes containing neurosecretory granules and immunore-activities for various neural markers suggested that these PNs showed more advanced neuronal differentiation. Two tumors, with the classical features of ES, showed no ultrastructural evidence of neuronal differentiation, although only gamma gamma neuron specific enolase (NSE) positivity was detected. Four undifferentiatied tumors with atypical features, included in this study as an atypical PNET group, showed certain neuroectodermal characteristics, such as ganglion cell differentiation, perivascular pseudorosettes, and gamma gamma NSE reactivity. It is concluded from this study that PNETs may include small round cell tumors showing different degrees of neuroectodermal differentiation and some histological variations. Acta Pathol Jpn 41: 444–454, 1991.